The present invention relates to an image processing device, an imaging device, an image processing method, and a non-transitory computer readable medium.
Recently, as the resolution of a solid-state imaging element such as a charge coupled device (CCD) image sensor and a complementary metal oxide semiconductor (CMOS) image sensor is enhanced, a demand for an information technology device having a photographing function such as a digital still camera, a digital video camera, a cellular phone such as a smartphone, and a personal digital assistant (PDA) is rapidly increasing. The information technology device having a capturing function as described above is referred to as an imaging device.
In such an imaging device, a contrast auto focus (AF) scheme or a phase difference AF scheme is employed as a focus control scheme which focuses on a major subject. Since the phase difference AF scheme may detect a focusing position with high precision at a high speed as compared to the contrast AF scheme, the phase difference AF scheme is widely employed in various imaging devices.
A solid-state imaging element mounted in an imaging device performing the focus control using the phase difference AF scheme uses, for example, a pair of phase difference detecting pixels having respective apertures of light shielding layers being off-centered in mutually reverse directions which are dispersedly provided on an entire surface of a capturing area (see Patent Literature 1 (JP-A-2012-4729) and Patent Literature 2 (JP-A-2010-62640)).
Since an area of the aperture of the light shielding layer in the phase difference detecting pixel is smaller than those of other general pixels, an output signal of the phase difference detecting pixel is inappropriate to be used as a captured image signal. Accordingly, the output signal of the phase difference detecting pixel needs to be corrected.
Patent Literature 1 and Patent Literature 2 disclose an imaging device simultaneously using interpolation correction processing of generating, through interpolation, an output signal of a phase difference detecting pixel using output signals of adjacent general pixels and gain correction processing of gain amplifying an output signal of a phase difference detecting pixel to be corrected.